With the maintenance, purchase and utilization analyzed, the medical engineer is oriented to enhancing the efficiency of the hospital and strengthening the construction of medical engineering department.

Objective As a signaling molecule,NO regulates key physiological processes and is closely related to periodontitis.To investigate the effect of flavonoid NO donor composite nanoparticles(G10@HAP/MSN@ZnO@COS)on osteogenic differentiation of periodontal ligament stem cells(PDLSCs)by regulating macrophage polarization.Methods The novel NO donor drug G10 was loaded on hydroxyapatite/mesoporous silicanant particles(HAP/MSN),filled with zinc oxide(ZnO),and then coated with chitosan(COS)to prepare composite nanoparticles(G10@HAP/MSN@ZnO@COS).The best concentration of G10@HAP/MSN@ZnO@COS was screened to promote cell proliferation by CCK-8 cell experiment.After the mouse mononuclear macrophages were stimulated by lipopo-lysaccharide,the mice were divided into four groups:Control group,G10 group,HAP/MSN@ZnO@COS group and G10@HAP/MSN@ZnO@COS group.Each group was cultured with fresh medium,5 μg/mL G10,5 μg/mL HAP/MSN@ZnO@COS and 5 μg/mL G10@HAP/MSN@ZnO@COS for 72 h respectively.ELISA and RT-qPCR were used to detect the expression of cytokines(TNF-α,IL-6,IL-1β,iNOS,IL-10)and mRNA expression in each group,and the phenotypic changes of M1/M2 were evaluated.The supernatant of each culture medium was used as conditioned medium to culture PDLSCs,and the osteogenic ability and cell miner-alization were evaluated by alkaline phosphatase activity test and alizarin red staining.Results CCK-8 experiment showed that G10@HAP/MSN@ZnO@COS of 5 μg/mL could significantly promote the proliferation of PDLSCs.The results of ELISA showed that compared with Control group,the expression of M1 type marker IL-1β,IL-6,TNF-α and iNOS in G10@HAP/MSN@ZnO@COS group was significantly decreased(P＜0.000 1),while the expression of M2 type marker IL-10 was significantly increased(P＜0.000 1).The results of RT-qPCR were consistent with those of ELISA,which showed that the expression of M1-related genes in G10@HAP/MSN@ZnO@COS group decreased significantly(P＜0.01).The results of alizarin red staining and alkaline phosphatase activity test showed that the number of mineralized nodules and alkaline phosphatase activity in G10@HAP/MSN@ZnO@COS-CM group were significantly higher than those in other groups(P＜0.000 1).Conclusion Composite nanoparticles(G10@HAP/MSN@ZnO@COS)can effectively inhibit the polarization of macrophages to M1 phenotype and promote it to M2 phenotypic polarization.The anti-inflammatory microenvironment regulated by G10@HAP/MSN@ZnO@COS can en-hance the osteogenic differentiation of PDLSCs.

Objective To evaluate and compare the treatment efficacy between concentrated growth factor(CGF)and blood clots(BC)as scaffolds in regenerative endodontic procedures(REPs).Methods Twenty young permanent teeth from 18 healthy children with pulp necrosis or periapical periodontitis were randomly divided into CGF group and BC group.In the CGF group(n=10),after ap-ical bleeding,CGF was inserted into the root canal as a stent.In the BC group(n=10),by stimulating apical bleeding,blood entered the root canal and produced blood clots as scaffolds.Clinical examination and apical X-ray shooting were conducted for each follow-up visit.Cone beam computed tomographic(CBCT)images were acquired preoperatively and at the 24-month recall.The increase of root length,root wall thickness,and newly-formed calcified tissue were calculated.Results The root length increased by(1.68±0.90)mm in the CGF group and(2.36±1.34)mm in the BC group.Root wall thickness increased by(0.44±0.34)mm in the CGF group and(0.50±0.31)mm in the BC group.There was no statistically significant difference in root lengthening and root wall thickening between two groups(P＞0.05).The amount of newly formed calcified tissue in the CGF group((22.13±19.12)mm3)was significantly less than that in the BC group((42.97±22.69)mm3)(P＜0.05).According to the goals for success outlined by American Association of Endodontists(AAE),90%(9/10)of the CGF cases and100%(10/10)of the BC cases achieved the primary and secondary goals(P＞0.05).40%of the CGF cases(4/10)and 60%of the BC cases(6/10)achieved the tertiary goal(P＞0.05).Conclusion CGF is found to be use-ful as a scaffold for REPs,but the success rate is slightly lower than that of BC group and the difference is not statistically significant.

Objective To measure the anatomical parameters of the first maxillary molars in children of different age groups and evaluate the age-related changes in dental crowns.Methods A retrospective analysis was conduc-ted on cone beam computed tomography(CBCT)images of 4-8-year-old children.NNT software was used to ana-lyze multiple important indicators of maxillary first molar.Results A total of 308 first maxillary molars,including 154 pediatric patients,were evaluated in this study.The thickness of the pulp apex H1(left,P=0.01;right,P=0.02)and the thickness of the pulp chamber floor H3(left and right P＜0.01)were positively correlated with age,while the height of the pulp cavity H2(left and right P＜0.01)and the height of the palate tip D1(left P=0.003,right P=0.002)showed a negative correlation with age.There was no significant correlation between the height of the buccal tip and age(P＞0.05).There were significant differences in H1 and H3 between the 4-year-old and 5-year-old age groups between the 8-year-old age group(P＜0.05),as well as significant differences in H2 and D1 between the 4-year-old and 5-year-old between the 6-year-old,7-year-old and 8-year-old age groups(P＜0.05).Conclusion The age-related changes in the crowns of the first maxillary molars are important references for the clinical treatment,and can be accurately measured through CBCT data.

Objective: To investigate the effect of Wnt3a on osteogenic differentiation of human dental pulp stem cells (DPSC). Methods: DPSCs were subjected to different concentrations of Wnt3a (0, 5, 20, 50 and 100 μg/L) and at seven days after culture the alkaline phosphatase (ALP) activity was tested. Mineralized nodule formation was examined by alizarin red staining. Osteogenic-related gene expression of bone sialoprotein (BSP), osteocalcin (OCN), collagen type Ⅰ (COL-Ⅰ), Runt-related transcription factor-2 (RUNX2) was examined by quantitative real-time PCR (qPCR). Results: After seven days of induction by DPSC, Wnt3a protein could inhibit the ALP activity (concentration 0: 1.076±0.203, 5 μg/L: 0.828±0.118, 20 μg/L: 0.505±0.044, 50 μg/L: 0.499±0.038, 100 μg/L: 0.483±0.060). The expression of OCN in 5 μg/L Wnt3a group (0.092±0.005) was lower than that in culture medium (0.858±0.190)(P<0.05). Alizarin red staining showed that 5 μg/L Wnt3a had no mineralization induction effect on DPSC. Conclusions Wnt3a could inhibit osteogenic differentiation of dental pulp stem cells.

Objective: Investigate osteogenic differentiation of canine periodontal ligament stem cells ( cPDLSCs) via over-expression ephrinB2 in cPDLSCs． Methods : cPDLSCs were isolated from the premolars and molars of Beagle．After transfected with EfnB2-GFP-Bsd and GFP-Bsd empty Vector，cPDLSCs were induced to osteogenic differentiation．Western blot was used to invest the expression of ephrinB2 protein．The effect of osteogenic differentiation of EfnB2-cPDLSCs and Vector-cPDLSCs were analyzed by RT-PCR , CCK-8，Alizarin-red S staining and ALP. Results: There was no significant difference in cell proliferation between EfnB2-cPDLSCs and Vector-cPDLSCs．While EfnB2-cPDLSCs displayed an enhanced ALP activity and more prominent mineralized nodules compared with Vector-cPDLSCs．The odonto-/ osteogenic genes in EfnB2-cPDLSCs were also highly enhanced． Conclusion The results of our study indicated that ephrinB2 gene-transfected cPDLSCs showed enhanced osteogenic differentiation.